/*********************************************************************
 * Copyright (C) 2007 Andrew Khan
 * <p>
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * <p>
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * <p>
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.write.biff;

import jxl.common.Logger;

import java.io.IOException;
import java.io.OutputStream;

/**
 * Used to generate the excel biff data in memory.  This class wraps a byte
 * array
 */
class MemoryDataOutput implements ExcelDataOutput {
    // The logger
    private static Logger logger = Logger.getLogger(MemoryDataOutput.class);

    /**
     * The excel data
     */
    private byte[] data;

    /**
     * The grow size for the array
     */
    private int growSize;

    /**
     * The current position within the array
     */
    private int pos;

    /**
     * Constructor
     */
    public MemoryDataOutput(int initialSize, int gs) {
        data = new byte[initialSize];
        growSize = gs;
        pos = 0;
    }

    /**
     * Writes the bytes to the end of the array, growing the array
     * as needs dictate
     *
     * @param d the data to write to the end of the array
     */
    public void write(byte[] bytes) {
        while (pos + bytes.length > data.length) {
            // Grow the array
            byte[] newdata = new byte[data.length + growSize];
            System.arraycopy(data, 0, newdata, 0, pos);
            data = newdata;
        }

        System.arraycopy(bytes, 0, data, pos, bytes.length);
        pos += bytes.length;
    }

    /**
     * Gets the current position within the file
     *
     * @return the position within the file
     */
    public int getPosition() {
        return pos;
    }

    /**
     * Sets the data at the specified position to the contents of the array
     *
     * @param pos the position to alter
     * @param newdata the data to modify
     */
    public void setData(byte[] newdata, int pos) {
        System.arraycopy(newdata, 0, data, pos, newdata.length);
    }

    /**
     * Writes the data to the output stream
     */
    public void writeData(OutputStream out) throws IOException {
        out.write(data, 0, pos);
    }

    /**
     * Called when the final compound file has been written.  No cleanup is
     * necessary for in-memory file generation
     */
    public void close() throws IOException {
    }
}
